Z2

Z2

The Z2 was a mechanical and relay computer created by Konrad Zuse in 1939. It was an improvement on the Z1, using the same mechanical memory but replacing the arithmetic and control logic with electromechanicalrelays circuits. The realization of the Z2 was helped financially by Dr. Kurt Pannke, who manufactured small calculating machines. The Z2 was completed in 1939 and presented to an audience of the Deutsche Versuchsanstalt für Luftfahrt ("German Laboratory for Aviation") in 1940 in Berlin-Adlershof. In this presentation the Z2 actually worked and could convince the DVL to partly finance the next design (namely the Z3). The machine, photographs of it and constructions plans for the Z2 were destroyed by the Allied bombing during World War II.

Supplement: Zuse designed the Z1 in 1935 to 1936 and built it from 1936 to 1938. The Z1 was wholly mechanical and only worked unreliably. Helmut Schreyer advised Zuse to use a different technology: As a doctoral student at the Berlin Institute of Technology in 1937 he worked on the implementation of Boolean operations and logic gates on the basis of vacuum tubes. In 1938 Schreyer demonstrated a circuit on this basis to a small audience, and explained his vision of an electronic computing machine – but since the largest operational electronic devices contained far fewer tubes this was considered practically infeasible. Zuse asked the German government for funding to replace the relays with fully electronic switches, but funding was denied during World War II since such development was deemed "not war-important". Zuse decided to implement the next machine (the Z3) based only on electromechanicalrelays. In contrast to the Z1, the Z2 used 16 bit fixed point arithmetic instead of 22 bitfloating point.